Facilities that comprise electrical systems may encounter voltage levels on their equipment that deviate from nominal values. For example, for an induction motor rated at 460 volts, an excessive voltage level above 500 volts may be present. End-users may errantly believe that if low voltage levels are unacceptable, then high voltage levels must be acceptable. However, the National Electrical Manufacturers Association (NEMA) Standards Publication No. MG 1 specifically points out that elevated voltage levels are just as damaging to the viability of a motor as low voltage levels (not to mention the adverse impact to the motor's efficiency). Other types of loads besides motors would also experience reduced efficiencies and shortened life due to extensive voltage deviations (e.g., lighting systems would experience shorter bulb life, reduced light efficacy, etc.). Providing each piece of equipment within the electrical system with the appropriate voltage level is important for that equipment's longevity and efficiency.
For example, when the equipment is an induction motor, at full load current, a ±10% voltage deviation can substantially increase the core losses of the motor resulting in overheating and potential damage to the motor's insulation over time. When starting a motor during severe undervoltage conditions, the developed torque may not be sufficient to allow the motor to come up to speed. Because motors are designed to operate most efficiently at their nameplate voltage rating, operating outside of a motor's recommended voltage rating will also decrease the motor's performance due to the introduction of additional losses into the electrical system.
By way of another example, when the equipment comprises fluorescent lamps, deviating outside of the recommended voltage range may have negative consequences including shortened lamp and/or ballast life, reduced efficacy, potential starting issues, and overheating.
Because maintaining the proper voltage levels is important to all aspects of an electrical system's operation and performance, it would be beneficial for end-users to continuously have a thorough awareness of the voltage levels throughout their electrical power system. Empirical data collected from an array of end-users has shown that even customers with extensive power monitoring systems (and data from those monitoring systems) are unaware of potentially damaging voltage levels that exist in their facilities. This “unawareness” is primarily due to the lack of experience and knowledge of their electrical system, their equipment, and of the monitoring system itself. The consequences to a specific end-user include the loss of productivity, revenue, equipment, reputation (due to not meeting deadlines), etc. The aggregate consequences of this problem to global resources and the economy are staggering with potentially billions of dollars unnecessarily wasted in energy and lost productivity costs.
Today, end-users cannot easily determine whether any component in their electrical system is operating at or near its desired nominal voltage rating. Voltage data can be accumulated at various monitoring points throughout the system, but only in an incoherent and disorganized manner that presents a large amount of non-contextualized voltage data to the end-user making it very tedious and time consuming to identify voltage deviations and their potential sources. Without any spatial or temporal context for the voltage data, an end-user may simply choose to ignore, overlook, or fail to realize voltage deviations in the electrical system and how those deviations might be affecting other equipment or overall system performance, an oversight which can disadvantageously result in inefficient operation, overheating, damage, mis-operation, or nuisance tripping.
What is needed, therefore, is an automated method for determining sources of anomalous voltage conditions by analyzing voltage data in spatial and (pseudo-) temporal context and for recommending modifications to the electrical system equipment to ameliorate or eliminate the anomalous voltage conditions.